1. Field of the Invention
This invention relates generally to apparatus for cutting honeycomb material and for breaking the cut chips and for removing the broken chaf material therefrom and, more particularly, to a rotatable assembly or tool for the continuous cutting of a workpiece of honeycomb material while continuously and simultaneously breaking chips from the cut honeycomb material and while continuously and simultaneously removing such broken chips or chaf away from the workpiece.
2. Description of the Prior Art
In the design and fabrication of many products, the ratio of strength to weight is of great significance. Typical products which require a high strength to weight ratio are civil aircraft, military aircraft, missiles, and the like. One material which has been found to offer excellent strength at reduced weight, thus making it highly suitable for use in such products, is a cellular or honeycomb material formed of symmetric walls of aluminum. Such material has, however, been found difficult to slice, cut, shape, or otherwise machine into desired configurations for incorporation into the intended final products. This is because honeycomb material is easily deformed during such machining.
When machining a workpiece of a readily deformable material such as a honeycomb material with conventional slicers, cutters, shapers, or the like, undesirable material deformations such as burrs, bent edges or similar deformations are too often created in the area where the tool contacts the material. Under such circumstances, the machined surface of the honeycomb material may become ragged or distorted rendering it unsuitable for use in the intended final product where a smooth surface is necessary for maximum compressive strength at the interface of the honeycomb surface to an adjacent structural component of the intended final product.
The difficulty of slicing, cutting, shaping or otherwise machining honeycomb material becomes even more pronounced when profiling, i.e., machining rounded contours or other non-planar surfaces. This is because the application of diverse or varying forces by the tool on the workpiece tends to distort the workpiece even more than during a planar cut. Similar difficulties arise when diverse or varying cutting forces are generated due to variations throughout the face of the honeycomb material. Such variations in the workpiece material may arise from different thicknesses in the wall material, different sizes and shapes of the spacings between the walls, or any other type of variation within the honeycomb material, from area to area.
One approach to the matchining of honeycomb material is described in U.S. Pat. No. 2,929,299 to Jenkins. According to that disclosure, a complex rotary cutting tool is employed for slicing a workpiece. The tool includes inner and outer rotary cutting discs having teeth directed in opposite directions. The discs are counter-rotated with respect to each other so that teeth on the exterior side of the upper disc can shred the cut cellular material adjacent the path of the cutter.
In another prior patent, U.S. Pat. No. 2,894,583 to Johnstad, a rotary cutting tool is disclosed for use on honeycomb material. The tool has a removable cutter blade comprising a peripherally sharpened ring of carbide material. The edges are not serrated and there is no disclosure of a chip breaker or chaf remover.
Additional rotary cutters are disclosed in prior patents but are not designed for machining honeycomb material. Among such additional prior patent disclosures are U.S. Pat. No. 1,559,680 to Denne which shows a disc cutter having a sinuous cutting edge which may advance toward, or recede from, the workpiece thus forming a succession of slicing cuts. U.S. Pat. No. 3,027,106 to Brooks shows the combination of a disc-shaped tooth cutter and a chip breaker drum joined for concurrent rotation. U.S. Pat. No. 692,028 to Page shows a power operated hand tool having a smooth edged cutting disc and an adjacent disc having a toothed edge. The edge of the smooth disc is recessed slightly from the edge of the toothed disc clamped thereto. The function of the spaced discs is to enable an operator to cut essentially parallel grooves. Lastly, U.S. Pat. No. 3,001,558 to Showler discloses a drum-shaped cutter head having cutter faces. The drum is removably attached to a lower support ring or disc.
Of the above-described prior disclosures, only those to Jenkins and Johnstad are suitable for machining workpieces of honeycomb material. Neither of these disclosures, however, teaches apparatus for slicing with one tool element while breaking the cut chips and removing the broken chaf with another tool element, all concurrently and in a continuous manner. All of the prior art tools require that the cut or sliced material be removed by hand by interrupting or stopping the cutting process.
As illustrated by the great number of prior patents, efforts are continuously being made in an attempt to accurately and conveniently slice, cut, shape, or otherwise machine workpieces of honeycomb material. Nothing in the prior art discloses or suggests the present inventive combination of component elements for accurately and conveniently machining a honeycomb workpiece. The present invention achieves its purposes, objectives, and advantages over the prior art through a new, useful, and unobvious combination of component elements for slicing or cutting a honeycomb workpiece continuously and concurrently while chopping or breaking chips of the cut material and while continuously and concurrently conveying or removing the separated broken chips or chaf, all with a minimum number of functioning parts, at a minimum of cost, and through the utilization of only readily available materials and conventional components.
These objectives and advantages should be construed as merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and advantages as well as a fuller understanding of the invention may be had by referring to the summary of the invention and detailed description describing the preferred embodiment of the invention in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.